Questions

Dolphins are the most highly intelligent mammals.

Here 6CO2 + 6H2O -----> C6H12O6 + 6O2 is the only option which best summarizes photosynthesis. We know that, photosynthesis is the reverse of cellular respiration in that carbon dioxide is used with water to form sugar, and oxygen is released.

Here, “to reach in time” should be used. Idiom in times mean, not late. with enough time, to be able to do something

Right ventricle (which pumps blood to the lungs), pulmonary artery (which carries blood to the lungs), and left atrium (which receives blood from the lungs) are involved directly in pulmonary circulation.

The Boston Marathon

Air is said to be saturated when it contains the maximum content of water vapour.

Each year, the World Meteorological Organisation (WMO), its members and the worldwide meteorological community around the world celebrate World Meteorological Day on 23rd March around a chosen theme. And this year the theme is "Understanding the cloud".

About 150 - 200 species of plant, insect, bird and mammal become extinct every day or 24 hrs.

This is not an accurate but an estimation by U.N. Convention on Biological Diversity and Global Extinction Rates. It is also said that current extinctions were 'up to 100 times higher than the background rate.'